A shipwreck in the east of the Democratic Republic of Congo (DRC) has killed more than 80 people, the Congolese president’s office said Wednesday.

“The President of the Republic is calling for an investigation into the true causes of this unfortunate incident, to prevent such a disaster from happening again in the future,” the office said in a statement.

The ship sank in the Kwa River, 70 kilometers away from the city of Mushie, in the province of Maï-Ndombe, according to the statement.

The president of the DRC, Félix Tshisekedi, expressed his condolences to the families of the victims.

Deadly shipwrecks are unfortunately frequent in the DRC as the country lacks road infrastructure and many people rely on boats to cross the many branches of the Congo River which runs alongside the country’s western border.

In October last year, at least 52 people were killed in the northwestern part of the country after a boat carrying more than 300 passengers capsized in the Congo River, authorities said at the time.

Another six people were killed months earlier in the DRC’s Lake Kivu after a boat carrying 150 villagers overturned.

The DRC only has one kilometer of paved road per 1,000 square kilometers compared to the 16 kilometers average for low-income countries, according to a report published by the World Bank.